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The interfacial and electrical characteristics of Ge metal–oxide–semiconductor(MOS) devices with a dual passivation layer of ZrON/GeON formed by NH_3- or N_2-plasma treatment are investigated. The experimental results show that the NH_3-plasma treated sample exhibits significantly improved interfacial and electrical properties as compared to the samples with N_2-plasma treatment and no treatment: a lower interface-state density at the midgap(1.64×10~(11)cm~(-2)·e V~(-1)/ and gate leakage current(9.32×10~(-5)A/cm~2 at V_(fb) +1 V), a small capacitance equivalent thickness(1.11 nm) and a high k value(32). X-ray photoelectron spectroscopy is used to analyze the involved mechanisms. It is indicated that more GeON and less GeO_x(x < 2) are formed on the Ge surface during NH_3-plasma treatment than the N_2-plasma treatment, resulting in a high-quality high-k/Ge interface, because H atoms and NH radicals in NH_3-plasma can enhance volatilization of the unstable low-k GeO_x, creating high-quality GeON passivation layer. Moreover, more nitrogen incorporation in ZrON/GeON induced by NH_3-plasma treatment can build a stronger N barrier and thus more effectively inhibit in-diffusion of O and Ti from high-k gate dielectric and out-diffusion of Ge.
The interfacial and electrical characteristics of Ge metal-oxide-semiconductor (MOS) devices with a dual passivation layer of ZrON / GeON formed by NH_3- or N_2-plasma treatment are investigated. The experimental results show that the NH_3-plasma treated sample significantly improved interfacial and electrical properties as compared to the samples with N_2-plasma treatment and no treatment: a lower interface-state density at the midgap (1.64 × 10-11 cm -2 · e V -1) / and gate leakage current (9.32 × 10 -5 A / cm 2 at V fb + 1 V), a small capacitance equivalent thickness (1.11 nm) and a high k value (32). It is indicated that more GeON and less GeO_x (x <2) are formed on the Ge surface during NH_3-plasma treatment than the N_2-plasma treatment, resulting in a high-quality high- k / Ge interface, because H atoms and NH radicals in NH 3-plasma can enhance volatilization of the unstable low-k GeO_x, creating hi gh-quality GeON passivation layer. Moreover, more nitrogen incorporation in ZrON / GeON induced by NH_3-plasma treatment can build a stronger N barrier and thus more effectively inhibit in-diffusion of O and Ti from high-k gate dielectric and out-diffusion of Ge.